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Silver nanoparticle-decorated polyaniline nanorods (AgNPs-PANINRs) and silver nanoparticle-decorated polyaniline nanotubes (AgNPs-PANINTs) composites were prepared through a one-step modified methods by immobilizing a mixture of AgNO3, aniline and ammonium per sulfate (APS) as an oxidant without adding any extra acids, templates or surface modifiers. The composites were characterized by using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The reactivity of the prepared composites towards hydrogen peroxide (H2O2) was analyzed using cyclic voltammetry and chronoamperometry. The AgNPs-PANINRs composite exhibits better electrochemical performance than the AgNPs-PANINTs composite due to higher content of silver nanoparticle (AgNPs). The sensor has a fast amperometric response time which less than 3 s. The detection limit and limit of quantification (S/N = 3) of two linear range (low and high concentration of H2O2) are estimated as 0.13 µM and 0.45 µM and 0.33 µM and 1.12 µM, respectively. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) decorated with silver nanoparticles (AgNPs), was electrochemically reduced on glassy carbon electrode (GCE) by an amperometry method (AMP-AgNPs-rGO/GCE). Then, Pyrrole was electropolymerized on the surface of the modified electrode through amperometry process in order to obtain nanofibers of polypyrrole (AMP-PpyNFs-AgNPs-rGO). Fourier-transform infrared transmission spectroscopy and X-ray diffraction approved that during the amperometry process, the GO and Ppy nanofibers were reduced and polymerized respectively and the silver nanoparticles were formed. Field emission scanning electron microscope images indicated that the silver nanoparticles were homogeneously distributed on the rGO surface with a narrow nano size distribution and polypyrrole synthesized in the form of nanofibers with diameter around 100 nm. The first linear section was in the range of 0.1–5 mM with a limit of detection of 1.099 and the second linear section raised to 90 mM with a correlation factor of 0.085 (S/N of 3) [ABSTRACT FROM AUTHOR]

A novel sensing composite of silver nanoparticles (AgNPs)-reduced graphene oxide (rGO)-carbon nanotube (MWCNT) was successfully synthesized by a simple one-step hydrothermal method without reducing agent. Mild reduction of GO was carried out under hydrothermal condition. While most conventional approaches make use of multistep chemical methods wherein strong reducing agents, such as hydrazine, hydroquinone, and sodium borohydride are employed, our method provides the notable advantage of a single-step reaction without employing any toxic solvent or reducing agent by providing a novel green synthetic route to produce the nanocomposites of rGO, carbon nanotube and silver. The results of X-ray diffraction (XRD) and Fourier-transform infrared transmission spectroscopy (FT-IR) confirmed the simultaneous formation of silver nanoparticles in the GO and MWCNT matrix. Field emission scanning electron microscope (FESEM) images and transmission electron microscopy (TEM) showed uniform distribution of nanometer-sized silver nanoparticles and narrow-sized MWCNT on GO sheets, which was achieved using silver ammonia complex as the precursor, instead of the commonly used silver nitrate. The composite exhibited excellent electrocatalytic activity for the reduction of H 2 O 2 with a fast amperometric response time less than 3 s. The electrocatalytic activity for the reduction was strongly affected by the concentration of silver ammonia solution in the nanocomposites, with the best electrocatalytic activity observed for the composite of 6:1 volume ratios of MWCNT–GO (3:1, v/v) to Ag(NH 3 ) 2 OH (0.04 M). The corresponding calibration curve for the current response showed a linear detection range of 0.1–100 mM ( R 2 = 0. 9985), while the limit of detection was estimated to be 0.9 μM. [ABSTRACT FROM AUTHOR]

Highlights • The sensor was fabricated based on a silver nanoparticles decorated polyaniline nanocomposite. • It has been applied to one-step pre-concentration, and analysis of the analyte. • The target analyte, anticancer drug 5‐ Fluorouracil in biological samples. Abstract A highly efficient electrochemical sensor for the analysis of anticancer drug 5-fluorouracil (5-FU), is fabricated based on silver nanoparticles-polyaniline nanotube (AgNPs@PANINTs). AgNPs@PANINTs nanocomposite has been synthesized by a simple one-step method. Synthesized AgNPs@PANINTs nanocomposite was studied by Fourier transform infrared spectrometry, Scanning Electron Microscopy and Energy Dispersive X-ray. The fabricated PANINTs@AgNPs PGE was applied to the electrochemical sensing of 5-FU. Cyclic voltammetry and differential pulse voltammetry experiments illustrated high electro activity for the AgNPs@PANINTs nanocomposite. The study was explored using the Taguchi experimental design method. Electrochemical measurements using differential pulse voltammetry showed a wide linear relationship between 5-FU concentration and peak height within the range 1.0–300.0 μM with a low detection limit (0.06 μM). Also, the fabricated sensor showed excellent selectivity in the presence of two anticancer drugs and a number of other interfering compounds. The as-prepared sensor showed to be a promising device for a simple, rapid, and direct analysis of 5-FU. [ABSTRACT FROM AUTHOR]